[mythtv] how do i: have multiple sources on the same tuner?

Bruce Markey bjm at lvcm.com
Thu Jun 9 19:24:01 UTC 2005

Simon Kenyon wrote:
> i have a 350 connected to a satellite box
> it has my analogue cable looped through it
> i control the sat box with lirc
> i want to tune some channels from the analogue cable and others from the sat 
> box. how do i do this? it seems in the setup it is an either/or situation.
> for channels from the cable i want it to tune to the appropriate frequency
> for channels from the sat i want it to tune to channel 69 and use the external 
> channel changer
> can i define two tuners (actually the same tuner) and assign a different 
> source to each?

Yes. This has come up before and I've tested it and it seems to
work save some ambiguity when changing channels in live TV but that
should not be an issue if you use the system primarily to record.
The setup program does not allow you to set two sources to the same 
input but you can manually modify the tables.

First of all, the best solution is connect the satellite box to the
card's s-video or composite input and connect the analog cable to
the coax input of the card rather than looping through the sat box.
That way each source is on it's own input and you can setup each
input normally.

You can't tune the frequency for the analog cable unless it is on
the Tuner (coax) input. Therefore, I have to assume that you are
running coax cable from the sat box to the card's tuner input and
the sat box output is modulated to 69 with the analog frequencies
passed through. If not, this example does not apply.

Create the card entry. Create sources for the sat channels and for
the analog channels. Under "Input connections", choose the tuner
input, select the sat source, set the channel change command and
set the "Preset tuner to channel" to "69". This is precisely what
this field is for, to set the card's tuner when tuning an external
device that is connected through the card's tuner input. Set the
start channel and Finish.

Next, you need to create an inaccurate entry that you can modify.
Select another input, Composite for example. Select the analog
channel source, leave the channel change command blank and most
definitely leave the preset channel blank. Set the start channel
and Finish.

$ mysql -u mythtv -pmythtv mythconverg
mysql> select * from cardinput;

There should be two entries for cardid 1. Input 1 with source 1,
Tuner0 and input 2 with source 2, Composite0. YMMV. Now, change
the fake entry to tuner's inputname:

mysql> update cardinput set inputname='Tuner0' where cardinputid=2;

(or whatever id and inputname are correct for your system).

You now have both entries associated with card 1, Tuner0. If channel
200 in on satellite (chanid 1200), it will call the external script
and set the card's tuner to the preset channel 69. If channel 13 is
on analog (chanid 2013), it will simply set the card's tuner to ch13.

This is undocumented and unsupported and I recall it chooses a known
chanid for recording just fine but changing channels in live TV could
get confused. Also, you can't use mythtv-setup to modify these entries
anymore. If you find this to be a problem, don't expect anyone
to fix it for you. If you can solve it, diff -u, spaces, no tabs.

--  bjm

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